The purpose of these experiments is to characterize two enzymes kynurenine hydroxylase and alpha glycerol phosphate dehydrogenase from developmental genetic and biochemical points of view. The regulation of the appearance of these enzymes during development is being studied genetically in whole animals. The molecular aspects of imaginal disc differentiation in vitro are being characterized for the purposes of studying the events of specific gene function during differentiation. The gene products alpha glycerol phosphate dehydrogenase and kynurenine hydroxylase are particularly useful for these studies. BIBLIOGRAPHIC REFERENCES: Sullivan, D.T. and M.C. Sullivan. Transport defects as the physiological basis of eye color mutants in Drosophila. Biochemical Genetics 13, 603-613, 1975. Moore, G. P. and D. T. Sullivan. Characterization of multiple forms of kynurenine formamidase in Drosophila. Biochim et Biophys. Acta 397, 468-477 1975.